Hi Philip, > -----Original Message----- > From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > Sent: Wednesday, March 16, 2011 9:01 PM > To: Nath, Arindam > Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; subhashj@xxxxxxxxxxxxxx; > linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx > Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs cards > > > Arindam, > > Thanks, > > There are a few other functions in the same file that should also be > changed for the same reason. I hope you mean by setting default bus speed mode and driver type for the card. If so, I will take care of them. Thanks, Arindam > > Philip > > On Mar 16, 2011, at 8:24 AM, Nath, Arindam wrote: > > > Hi Philip, > > > > > >> -----Original Message----- > >> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > >> Sent: Wednesday, March 16, 2011 8:48 PM > >> To: Nath, Arindam > >> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; subhashj@xxxxxxxxxxxxxx; > >> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx > >> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs > cards > >> > >> > >> On Mar 16, 2011, at 8:00 AM, Nath, Arindam wrote: > >> > >>> Hi Philip, > >>> > >>> > >>>> -----Original Message----- > >>>> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > >>>> Sent: Wednesday, March 16, 2011 8:22 PM > >>>> To: Nath, Arindam > >>>> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; > subhashj@xxxxxxxxxxxxxx; > >>>> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; > anath.amd@xxxxxxxxx > >>>> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs > >> cards > >>>> > >>>> > >>>> On Mar 16, 2011, at 7:32 AM, Nath, Arindam wrote: > >>>> > >>>>> Hi Philip, > >>>>> > >>>>> > >>>>>> -----Original Message----- > >>>>>> From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > >>>>>> Sent: Wednesday, March 16, 2011 7:56 PM > >>>>>> To: Nath, Arindam > >>>>>> Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; > >> subhashj@xxxxxxxxxxxxxx; > >>>>>> linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; > >> anath.amd@xxxxxxxxx > >>>>>> Subject: Re: [PATCH v2 07/12] mmc: sd: set current limit for uhs > >>>> cards > >>>>>> > >>>>>> > >>>>>> On Mar 4, 2011, at 3:32 AM, Arindam Nath wrote: > >>>>>> > >>>>>>> We decide on the current limit to be set for the card based on > >> the > >>>>>>> Capability of Host Controller to provide current at 1.8V > >>>> signalling, > >>>>>>> and the maximum current limit of the card as indicated by CMD6 > >>>>>>> mode 0. We then set the current limit for the card using CMD6 > >> mode > >>>> 1. > >>>>>>> > >>>>>>> Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx> > >>>>>>> --- > >>>>>>> drivers/mmc/core/sd.c | 45 > >>>>>> +++++++++++++++++++++++++++++++++++++++++++++ > >>>>>>> drivers/mmc/host/sdhci.c | 24 ++++++++++++++++++++++++ > >>>>>>> include/linux/mmc/card.h | 9 +++++++++ > >>>>>>> include/linux/mmc/host.h | 1 + > >>>>>>> 4 files changed, 79 insertions(+), 0 deletions(-) > >>>>>>> > >>>>>>> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > >>>>>>> index ec0d8e6..df98a2c 100644 > >>>>>>> --- a/drivers/mmc/core/sd.c > >>>>>>> +++ b/drivers/mmc/core/sd.c > >>>>>>> @@ -550,6 +550,46 @@ static int sd_set_bus_speed_mode(struct > >>>> mmc_card > >>>>>> *card, u8 *status) > >>>>>>> return 0; > >>>>>>> } > >>>>>>> > >>>>>>> +static int sd_set_current_limit(struct mmc_card *card, u8 > >> *status) > >>>>>>> +{ > >>>>>>> + struct mmc_host *host = card->host; > >>>>>>> + int mmc_host_max_current_180, current_limit; > >>>>>>> + int err; > >>>>>>> + > >>>>>>> + /* sanity check */ > >>>>>>> + if (!host->ops->get_max_current_180) > >>>>>>> + return 0; > >>>>>> > >>>>>> a better name would be get_max_current rather than > >>>> get_max_current_180 > >>>>> > >>>>> The Max Current Capabilities register reports maximum currents > for > >>>> 1.8V, 3.0V and 3.3V. Since we are only interested in the maximum > >>>> current at 1.8V, so I have added *_180 to the variable names to > make > >> it > >>>> explicit. > >>>> > >>>> understand but that is the usage now and if we need to extend the > >> code > >>>> the name becomes misleading. > >>> > >>> Okay. I will remove *_180 in next version. > >>> > >>>>> > >>>>>> > >>>>>> do you want a test for get_max_current_180 < 400 ? and return 0 > >>>> have > >>>>>> it do the switch > >>>>>> by setting the value ? > >>>>> > >>>>> As mentioned in the Physical Layer spec v3.01, <400mA falls under > >> the > >>>> default current limit, so we don't need to set it in case any or > all > >> of > >>>> the above conditions fail. > >>>> > >>>> if future cards have memory or power is not removed they will they > >>>> retain the old setting ? if so better to explicitly initialize. > >>> > >>> Can you please elaborate this a little further? > >> > >> Power to the sd slot is supplied via a regulator. This is turned on > at > >> power on. > >> sometime in the future a reboot is done. power is NOT removed. The > >> device does not reset > >> into the default state. Have seen this on some boards. > > > > Thanks for the explanation. I will modify code to set the default > current limit for the card. > > > > Regards, > > Arindam > > > >> > >>> > >>> Thanks, > >>> Arindam > >>> > >>>> > >>>>> > >>>>> Thanks, > >>>>> Arindam > >>>>> > >>>>>>> + > >>>>>>> + /* Maximum current supported by host at 1.8V */ > >>>>>>> + mmc_host_max_current_180 = host->ops- > >>> get_max_current_180(host); > >>>>>>> + > >>>>>>> + if (mmc_host_max_current_180 >= 800) { > >>>>>>> + if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_800) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_800; > >>>>>>> + else if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_600) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_600; > >>>>>>> + else if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_400) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_400; > >>>>>>> + } else if (mmc_host_max_current_180 >= 600) { > >>>>>>> + if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_600) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_600; > >>>>>>> + else if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_400) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_400; > >>>>>>> + } else if (mmc_host_max_current_180 >= 400) > >>>>>>> + if (card->sw_caps.uhs_curr_limit & > >> SD_MAX_CURRENT_400) > >>>>>>> + current_limit = SD_SET_CURRENT_LIMIT_400; > >>>>>> > >>>>>> or > >>>>>> else > >>>>>> current_limit = SD_SET_CURRENT_LIMIT_200; > >>>>>>> + > >>>>>>> + err = mmc_sd_switch(card, 1, 3, current_limit, status); > >>>>>>> + if (err) > >>>>>>> + return err; > >>>>>>> + > >>>>>>> + if (((status[15] >> 4) & 0x0F) != current_limit) > >>>>>>> + printk(KERN_WARNING "%s: Problem setting current > >> limit!\n", > >>>>>>> + mmc_hostname(card->host)); > >>>>>>> + > >>>>>>> + return 0; > >>>>>>> +} > >>>>>>> + > >>>>>>> /* > >>>>>>> * UHS-I specific initialization procedure > >>>>>>> */ > >>>>>>> @@ -590,6 +630,11 @@ static int mmc_sd_init_uhs_card(struct > >>>> mmc_card > >>>>>> *card) > >>>>>>> > >>>>>>> /* Set bus speed mode of the card */ > >>>>>>> err = sd_set_bus_speed_mode(card, status); > >>>>>>> + if (err) > >>>>>>> + goto out; > >>>>>>> + > >>>>>>> + /* Set current limit for the card */ > >>>>>>> + err = sd_set_current_limit(card, status); > >>>>>>> > >>>>>>> out: > >>>>>>> kfree(status); > >>>>>>> diff --git a/drivers/mmc/host/sdhci.c > b/drivers/mmc/host/sdhci.c > >>>>>>> index f127fa2..245cc39 100644 > >>>>>>> --- a/drivers/mmc/host/sdhci.c > >>>>>>> +++ b/drivers/mmc/host/sdhci.c > >>>>>>> @@ -1462,12 +1462,36 @@ static int > >>>>>> sdhci_start_signal_voltage_switch(struct mmc_host *mmc) > >>>>>>> return -EAGAIN; > >>>>>>> } > >>>>>>> > >>>>>> > >>>>>> better name is sdhci_get_max_current > >>>>>> > >>>>>>> +static int sdhci_get_max_current_180(struct mmc_host *mmc) > >>>>>>> +{ > >>>>>>> + struct sdhci_host *host; > >>>>>>> + u32 max_current_caps; > >>>>>>> + unsigned long flags; > >>>>>>> + int max_current_180; > >>>>>>> + > >>>>>>> + host = mmc_priv(mmc); > >>>>>>> + > >>>>>>> + spin_lock_irqsave(&host->lock, flags); > >>>>>>> + > >>>>>>> + max_current_caps = sdhci_readl(host, SDHCI_MAX_CURRENT); > >>>>>>> + > >>>>>>> + spin_unlock_irqrestore(&host->lock, flags); > >>>>>>> + > >>>>>>> + /* Maximum current is 4 times the register value for 1.8V > >> */ > >>>>>>> + max_current_180 = ((max_current_caps & > >>>>>> SDHCI_MAX_CURRENT_180_MASK) >> > >>>>>>> + SDHCI_MAX_CURRENT_180_SHIFT) * > >>>>>>> + SDHCI_MAX_CURRENT_MULTIPLIER; > >>>>>> > >>>>>> SDHCI_MAX_CURRENT_SHIFT is better name. > >>>>>> > >>>>>>> + > >>>>>>> + return max_current_180; > >>>>>>> +} > >>>>>>> + > >>>>>>> static const struct mmc_host_ops sdhci_ops = { > >>>>>>> .request = sdhci_request, > >>>>>>> .set_ios = sdhci_set_ios, > >>>>>>> .get_ro = sdhci_get_ro, > >>>>>>> .enable_sdio_irq = sdhci_enable_sdio_irq, > >>>>>>> .start_signal_voltage_switch = > >>>>>> sdhci_start_signal_voltage_switch, > >>>>>>> + .get_max_current_180 = sdhci_get_max_current_180, > >>>>>> > >>>>>> .get_max_current = sdhci_get_max_current; > >>>>>>> }; > >>>>>>> > >>>>>>> > >>>>>> > >>>> > >> > /********************************************************************** > >>>>>> *******\ > >>>>>>> diff --git a/include/linux/mmc/card.h > b/include/linux/mmc/card.h > >>>>>>> index 0b24c41..a6811ae 100644 > >>>>>>> --- a/include/linux/mmc/card.h > >>>>>>> +++ b/include/linux/mmc/card.h > >>>>>>> @@ -98,6 +98,15 @@ struct sd_switch_caps { > >>>>>>> #define SD_DRIVER_TYPE_C 0x04 > >>>>>>> #define SD_DRIVER_TYPE_D 0x08 > >>>>>>> unsigned int uhs_curr_limit; > >>>>>>> +#define SD_SET_CURRENT_LIMIT_200 0 > >>>>>>> +#define SD_SET_CURRENT_LIMIT_400 1 > >>>>>>> +#define SD_SET_CURRENT_LIMIT_600 2 > >>>>>>> +#define SD_SET_CURRENT_LIMIT_800 3 > >>>>>>> + > >>>>>>> +#define SD_MAX_CURRENT_200 (1 << SD_SET_CURRENT_LIMIT_200) > >>>>>>> +#define SD_MAX_CURRENT_400 (1 << SD_SET_CURRENT_LIMIT_400) > >>>>>>> +#define SD_MAX_CURRENT_600 (1 << SD_SET_CURRENT_LIMIT_600) > >>>>>>> +#define SD_MAX_CURRENT_800 (1 << SD_SET_CURRENT_LIMIT_800) > >>>>>>> }; > >>>>>>> > >>>>>>> struct sdio_cccr { > >>>>>>> diff --git a/include/linux/mmc/host.h > b/include/linux/mmc/host.h > >>>>>>> index 4dfff6d..e84cd05 100644 > >>>>>>> --- a/include/linux/mmc/host.h > >>>>>>> +++ b/include/linux/mmc/host.h > >>>>>>> @@ -128,6 +128,7 @@ struct mmc_host_ops { > >>>>>>> void (*init_card)(struct mmc_host *host, struct mmc_card > >> *card); > >>>>>>> > >>>>>>> int (*start_signal_voltage_switch)(struct mmc_host > >> *host); > >>>>>>> + int (*get_max_current_180)(struct mmc_host *mmc); > >>>>>>> }; > >>>>>>> > >>>>>>> struct mmc_card; > >>>>>>> -- > >>>>>>> 1.7.1 > >>>>>>> > >>>>>> > >>>>> > >>>>> > >>>> > >>> > >>> > >> > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
